Improvement in caps for fruit-jars



H. WRIGHT.

Fruitlar Cap.

Patented March 22, 1870.

Ira/611167" fitaiird gala fiat-tent can.

HOMER WRIGHT, OF PITTSB URG, PENSY LVANIA, ASSIGNORTO HIMSELF, HENRY H., AND BENJAMIN Fl COLLINS, OF PLACE.

- Letters Patent No. 101,074, dated March 22, 1870.

IMPROVEMENT IN CAPS FOR FRUIT-JARS.

{1311a- Schedule referred to in thele Letters Patent and makmg part of the same of the jar, and has for its object the providing of inclines on the top of the lid for the purpose of tightening the clamp, and thus increasing the pressure of the lid; also, raising the metal in such a manner as to strengthen the top of the lid and supportthe inclines. To enable those skilled in the art to make and use my invention, I will proceed to describe one practical mode of carrying it into effect, in connection with a glass jar, gum gasket, and clamp,(made of Wire.)

In sealing fruit in glass jars on which a gum gasket is used in connection with a common. fiat-toptinlid and clamp, it is found diilicult to make an air-tight joint, owing to the variations in the glass and consequent unequal pressure, or want of pressure suflicient in the clamp. Them-too, the lid is liable to give way immediately under the clamp, when the parts not subject to pressure are apt to spring up, and thus admit the air. To obviate these objections, I proceed as follows: .1 make my lids of sheet-tin, by pressure, in the ordinary manner, and of proper size' to fit'any given jar of the class mentioned above, and on the outer diameter of the top of the lid I raise up two double inclines A, one on either side, each tapering from its center, which is its highest point. Across the surface of these inclines I make a series of notches, B, at equal distances apart, and all radiating toward the center of application of the clamp simple and easy, operating with equal facility when turned to the right or to the left.

The lid is further strengthened by two raised segments, D, extending from points on either side where the inclines terminate, and the centre of the lid is slightly raised, E, for the same purpose.

Between the central raise and the inclines the metal is raised, F, for the double purpose of supporting the inclines and to prevent the tin breaking in the stamping on the inclines, which is an important matter, as without this raise every lid would break.

It is obvious that substantially the same result can be attained with single inclines on the lid instead of the double, but with less .strength and less facility in the adjustment of the clamp.

I claim A metal cap having inclines A and indentations B formed upon its outer upper edge, substantially as described.

HOMER WRIGHT.

Witnesses:

A. THOMAS, M. NICHOLS. 

